"To all who feel bullied or thin-shamed during our recent social media discussion: If you know me or are familiar with any of my beliefs or stances you'll recognize that it isn't in my character to tear down anyone for 'being who they are,'" Seyfried wrote.

"However, as I'm acutely aware, there's a price tag for the group of people who find themselves with a platform to stand on. You have to be aware of the message you're sending and be able to back it up when faced with criticism (not just praise)," she said.

The Mean Girls star stood by her comments about Charnas promoting an "unhealthy body image," but said she regrets specifically targeting the mom-of-two.

"The only thing I'd take back is exactly how I started this debate. I desperately wish it hadn't targeted (or blasted) one person (there are MANY who engage in this questionable messaging) and instead started a cleaner, general conversation," Seyfried said. "No one needs to tear anyone apart. And I regret that it's present right now."

"To the lady in question: I'm sorry for the truly negative feels you've endured because of this," she concluded.

Charnas, who welcomed her second child in June 2018, had shared a bikini photo Tuesday, writing, "Proud of my body after two kids." Seyfried re-posted a comment her friend left on Charnas' photo, which said the blogger was "glorifying an unhealthy body image."

"A friend of mine wrote on an influencer's feed because (IMO) it had to be said," Seyfried wrote.

"If we're ready to get paid for flaunting our lifestyle (and inspiring some in the meantime) we have to be open to the discussions surrounding what we're promoting," she said of Charnas, who has 1.2 million Instagram followers.

People said Charnas clapped back on Instagram Stories after blocking Seyfried and her friend.

"Why am I being bullied for posting myself in a bathing suit? I should be punished because I'm thin and worked hard to be fit after giving birth to two kids? I'm not responsible for making people feel good about themselves," she wrote.

Seyfried is parent to 2-year-old daughter Nina with her husband, actor Thomas Sadoski. She will next star in an adaptation of the Garth Stein book The Art of Racing in the Rain, which opens in theaters Aug. 9.